release/21.x: [rtsan] Handle attributed IR function declarations (#169577) #170641
+14
−0
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Addresses llvm#169377. Previously, the RealtimeSanitizer pass only handled attributed function _definitions_ in IR, and we have recently found that attributed function _declarations_ caused it to crash. To fix the issue, we must check whether the IR function is empty before attempting to do any manipulation of its instructions. This PR: - Adds checks for whether IR `Function`s are `empty()` ~~in each relevant~~ at the top-level RTSan pass routine - ~~Removes the utility function `rtsanPreservedCFGAnalyses` from the pass, whose result was unused and which would otherwise have complicated the fix~~ (cherry picked from commit 5d4c441)
Member
Author
|
@cjappl What do you think about merging this PR to the release branch? |
Member
Author
|
@llvm/pr-subscribers-llvm-transforms @llvm/pr-subscribers-compiler-rt-sanitizer Author: None (llvmbot) ChangesBackport 5d4c441 Requested by: @davidtrevelyan Full diff: https://github.com/llvm/llvm-project/pull/170641.diff 2 Files Affected:
diff --git a/llvm/lib/Transforms/Instrumentation/RealtimeSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/RealtimeSanitizer.cpp
index 5ef6ffb58a7c1..667fdb746175f 100644
--- a/llvm/lib/Transforms/Instrumentation/RealtimeSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/RealtimeSanitizer.cpp
@@ -90,6 +90,9 @@ PreservedAnalyses RealtimeSanitizerPass::run(Module &M,
[&](Function *Ctor, FunctionCallee) { appendToGlobalCtors(M, Ctor, 0); });
for (Function &F : M) {
+ if (F.empty())
+ continue;
+
if (F.hasFnAttribute(Attribute::SanitizeRealtime))
runSanitizeRealtime(F);
diff --git a/llvm/test/Instrumentation/RealtimeSanitizer/rtsan_attrib_declare.ll b/llvm/test/Instrumentation/RealtimeSanitizer/rtsan_attrib_declare.ll
new file mode 100644
index 0000000000000..3526a010ce489
--- /dev/null
+++ b/llvm/test/Instrumentation/RealtimeSanitizer/rtsan_attrib_declare.ll
@@ -0,0 +1,11 @@
+; RUN: opt < %s -passes='rtsan' -S | FileCheck %s
+
+declare void @declared_realtime_function() sanitize_realtime #0
+
+declare void @declared_blocking_function() sanitize_realtime_blocking #0
+
+; RealtimeSanitizer pass should ignore attributed functions that are just declarations
+; CHECK: declared_realtime_function
+; CHECK-EMPTY:
+; CHECK: declared_blocking_function
+; CHECK-EMPTY:
|
|
|
Contributor
|
Tagging @inkreasing for visibility |
cjappl
approved these changes
Dec 4, 2025
Contributor
cjappl
left a comment
cjappl
left a comment
There was a problem hiding this comment.
LGTM. Definitely a bug we want fixed for Rust as soon as feasible.
Seems low risk for regression.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Backport 5d4c441
Requested by: @davidtrevelyan